System and method for casting and rolling metal

ABSTRACT

The invention essentially relates to a device and a method for casting and rolling metal, wherein at least one first and one second casting line for casting slabs and a rolling train for rolling the casted slabs are provided. The first casting line is designed as a horizontal thin-slab casting system ( 1 ) which comprises at least one dispensing vessel ( 5 ) for a melt and a conveyor belt ( 6 ) running horizontally downstream of the at least one dispensing vessel ( 5 ) in the casting direction. The second casting system is likewise designed as a horizontal thin-slab casting system ( 1 ) and/or as a vertical thin-slab casting system ( 2 ), which comprises at least one mold ( 4 ) for vertically casting slabs and a bending and straightening device ( 7 ) for bending and straightening the vertically casted slabs into a horizontal position. A rolling train ( 11 ) for rolling the casted slabs lies downstream of the at least two casting lines, and the at least two casting lines are designed such that the slabs, each of which is cast using one of the at least two casting lines, can be conveyed to the rolling train ( 11 ).

FIELD OF THE INVENTION

The invention concerns an installation and a method for casting and rolling metal, especially steel, by means of casting installations and a downstream rolling train.

For the sake of clarity, we shall first define a few terms that are used synonymously in the context of the present specification. The terms “thin slabs” and “slabs” each refer to very thin slabs (5-35 mm thick), thin slabs (35-90 mm thick), medium-thickness slabs (90-150 mm thick), or near-net strip (20-50 mm thick).

In the context of the present specification, the term “horizontal thin-slab casting installation” is synonymous with a horizontal strip casting installation, especially a BCT installation (belt casting technology) or a DSC installation (direct strip casting).

In the context of the present specification, the term “vertical thin-slab casting installation” covers especially the following types of installations: a thin-slab casting installation in accordance with compact strip production (CSP), a vertical casting installation with a downstream bending and straightening installation for a strand with a still-liquid crater, a vertical casting installation with a downstream bending and straightening installation for a completely solidified strand (e.g., a CSP installation), or a bow-type casting installation.

PRIOR ART

The document EP 1 708 830 B1 discloses a CSP installation designed for the production of thin slabs with a thickness of about 50 mm. In particular, this document describes a two-strand installation. The strands produced in this installation are fed to a common rolling train. In this connection, the strands are conveyed by so-called pivoting conveyors. In addition, there is a parallel rolling installation for conventional thick slabs or medium-thickness slabs, which is arranged downstream of a two-stand blooming train, with which slabs to be charged to the CSP line are reduced to a thickness of about 50 mm. An upstream roughing stand or plate-rolling stand is provided for charging slabs into the CSP line.

In patent EP 1 318 876 B1, two CSP installations with a downstream rolling train are provided. One of these installations is used to produce carbon steel, while the other is used to produce special steel. The steel slabs are bent in these CSP installations.

In view of the prior art described above, the technical objective of the present invention is to further develop a previously known installation and a previously known method for casting and rolling metal in such a way that they are also suitable for the production of high alloy steels or super alloy steels and the production of thin strip.

DISCLOSURE OF THE INVENTION

The technical objective is achieved by the installation of the invention for casting and rolling metal, which comprises at least a first and a second casting line for casting slabs and means for conveying slabs cast in the first casting line into the second casting line, as well as a rolling train for rolling the cast slabs, wherein the first casting line is designed as a horizontal thin-slab casting installation, which comprises at least one charging vessel for a melt and one horizontally running conveyor belt downstream of the one or more charging vessels in the casting direction, and wherein the second casting line is likewise designed as a horizontal thin-slab casting installation or as a vertical thin-slab casting installation, which comprises at least one mold for the vertical casting of slabs and a bending and straightening device for bending the vertically cast slab into a horizontal position, and wherein a rolling train for rolling the cast slabs is arranged downstream of one of the two casting lines, and the two or more casting lines and the means of conveyance are designed in such a way that the slabs cast with each one of the two or more casting lines can be fed to the rolling train.

The installation in accordance with the invention allows better utilization of a rolling train. In addition, an existing rolling train can be better utilized by expansion with additional casting lines. In addition, the provision of a horizontal thin-slab casting installation makes it possible to produce high alloy or super alloy steels, including, for example, crack-sensitive steels and especially steels with a high aluminum content, since the thin slabs do not come into contact with casting flux in the horizontal thin-slab casting installation as a result of the traveling mold or conveyor belt. As a result of the combination with the horizontal thin-slab casting installation, a fine grain structure is also realized due to rapid solidification and a low segregation tendency. Furthermore, oscillation marks on the cast product can be avoided by a traveling mold. Possible cracking, bending or straightening damage is also avoided. In addition, standard steels can also be produced by the additionally provided thin-slab casting installation. All together, the production program or spectrum is thus considerably expanded compared to known installations. The use of thin-slab technology also makes it possible directly to produce strips with a thickness of less than 15 mm, which greatly reduces the rolling work in the rolling train.

In a preferred embodiment of the installation, each of the two or more casting lines is designed as a horizontal thin-slab casting installation, which is followed by the rolling train for rolling the slabs cast in the horizontal thin-slab casting installations. With this type of arrangement, even an installation that comprises only horizontal thin-slab casting installations can be operated in a cost-efficient way.

In another preferred embodiment of the installation, the two or more casting lines are designed in a way that makes it possible to cast slabs of such small thickness that a roughing stand is not necessary for rolling the cast slabs before they enter the rolling train. This type of arrangement saves space, energy, and expense.

In another preferred embodiment of the installation, the thin-slab casting installation is designed for casting and rolling slabs with a thickness of 40 mm to 1.20 mm, and/or the horizontal thin-slab casting installation is designed for casting and rolling slabs with a thickness of 5 mm to 35 mm and preferably 10 mm to 20 mm.

In another preferred embodiment of the installation, the one or more horizontal thin-slab casting installations are designed for casting high alloy and super alloy steels.

In another preferred embodiment of the installation, at least one temperature-adjusting device, especially a furnace, is arranged downstream of the conveyor belt of the one or more thin-slab casting installations in the direction of casting, and/or at least one temperature-adjusting device, especially a furnace, is arranged downstream of the bending device of the one or more thin-slab casting installations in the direction of casting.

In another preferred embodiment of the installation, the means for conveying slabs cast in one of the two or more casting lines to another of the two or more casting lines consist of conveyors, especially pivoting conveyors, and/or the conveyors are designed in such a way that the slabs are conveyed into a section of the temperature-adjusting device of the other of the two or more casting lines.

In another preferred embodiment of the installation, the two or more casting lines are arranged parallel to each other and/or side by side.

In another preferred embodiment of the installation, the installation comprises a total of three casting lines arranged parallel side by side, and the rolling train for rolling the slabs cast in the casting lines is arranged downstream of the middle of the three casting lines in the direction of casting.

In addition, the invention comprises a method for casting and rolling metal with at least two casting lines, which hereafter are also referred to as the first and second casting lines, for casting slabs, especially with the installation according to one or more of the embodiments described above, wherein thin slabs are cast horizontally in at least one of the casting lines, and thin slabs are likewise horizontally cast in at least one other casting line, and/or slabs are cast vertically and/or in a curve and are bent into a horizontal direction during or after the casting, wherein the cast slabs are then fed to exactly one rolling train. The advantages of the method of the invention are largely the same as those of the installation of the invention.

In a preferred embodiment of the method, the horizontally cast thin slabs consist of steels with an aluminum content of up to 10%.

In another preferred embodiment of the method, the horizontally cast thin slabs consist of steels with an aluminum content of 1-3%.

In another preferred embodiment of the method, the horizontally cast thin slabs consist of carbon steels, low alloy steels, high alloy steels or peritectic steels.

BRIEF DESCRIPTION OF THE FIGURES

The figures, which illustrate specific embodiments of the invention, will now be briefly described. Further details are provided in the Detailed Description of the Specific Embodiments that follows the brief description.

FIG. 1 a is a schematic top view of an embodiment of an installation of the invention, in which a horizontal thin-slab casting installation can be connected by pivoting conveyors with a two-strand thin-slab casting installation.

FIG. 1 b is a perspective view of the installation according to FIG. 1 a but with a common distributing launder for the two-strand vertical thin-slab casting installation.

FIG. 1 c is a schematic top view of an embodiment of an installation of the invention analogous to FIG. 1 a but with a shorter temperature-adjusting section.

FIG. 1 d is a perspective view of the installation according to FIG. 1 c.

FIG. 2 a is a schematic top view of an embodiment of the invention with a thin-slab casting installation together with a downstream roiling train and two horizontal thin-slab casting installations that can be connected with this installation by means of pivoting conveyors.

FIG. 2 b is a perspective view of the installation according to FIG. 2 a.

FIG. 3 a is a schematic top view of an embodiment of the invention with a horizontal thin-slab casting installation together with a downstream rolling train and two additional horizontal thin-slab casting installations that can be connected with this installation by means of pivoting conveyors.

FIG. 3 b is a perspective view of the installation according to FIG. 3 a.

FIG. 4 a is a schematic top view of an embodiment of the invention with three horizontal thin-slab casting installations, which are fed by a common distributing launder and can be connected with one another by pivoting conveyors, and which have a common downstream rolling train.

FIG. 4 b is a perspective view of the installation according to FIG. 4 b.

DETAILED DESCRIPTION OF THE SPECIFIC EMBODIMENTS

FIG. 1 a shows a specific embodiment of an installation of the invention with two CSP installations 2 or vertical thin-slab casting installations 2. These vertical thin-slab casting installations 2 in themselves are already well known. In these installations 2, a strand is first vertically cast with a mold 4 and then bent by a bending device 7 and subsequently straightened with a straightening unit. Optionally, a cutting unit 8 or shears 8 are provided farther along in the direction of casting. The slabs then arrive in a downstream temperature-adjusting unit 9, especially a furnace 9, where, for example, they can be heated or held at a certain temperature.

A horizontal thin-slab casting installation 1 is arranged alongside the two CSP casting installations 2. This installation is preferably located parallel next to one of the vertical thin-slab casting installations 2. The installation 1, which is shown at the top in FIG. 1 a, has a charging vessel 5 for the melt and a conveyor belt 6, onto which the liquid metal is guided and on which the metal strip begins to solidify. This is followed downstream in FIG. 1 a by a temperature-adjusting zone or unit 9.

The embodiment illustrated in FIG. 1 is also provided with pivoting conveyors 10 for conveying the slabs from the end of the two outer casting lines to the casting line arranged in the middle. Experts in this field are already familiar with the design of pivoting conveyors 10. Alternatively, parallel conveyors, which in themselves are already well known, can be provided in accordance with the invention. Optionally, the temperature-adjusting zones 9 can be designed as roller hearth furnaces; in particular, the conveyors 10 are designed as (tunnel) furnace conveyors. Suitable use of the conveyors 10 allows slabs to be conveyed from each of the three installations 1, 2 to a downstream rolling train 11. In particular, as shown in the drawings, a total of three casting lines or installations 1, 2 are arranged side by side. The rolling train 11 is preferably located in line with the middle of the three casting lines. The slabs produced by the outer lines can then be conveyed by the conveyors 10 into a section of the temperature-adjusting unit 9 that is in line with the rolling train 11. In general, for one or more of the casting lines, it is also possible to charge slabs from the outside into one of the casting lines. Furthermore, an additional roughing stand can also be provided in one of the casting lines for rolling slabs thus charged. The design of the rolling train 11 arranged downstream of the casting installations 1, 2, which preferably comprises several roll stands 12, is not the focus of the invention and can thus be of any known type.

FIG. 1 b shows the installation according to FIG. 1 a, wherein the molds 4 of the vertical thin-slab casting and rolling installation are supplied with melt by a common distributing launder.

The installation according to FIGS. 1 a and 1 b makes it possible to combine the advantages of horizontal thin-slab casting installations 1 with those of vertical thin-slab casting installations 2. The rolling train 11 is fully utilized, since three casting lines supply one rolling train 11. If a thin-slab casting installation 1 were provided by itself, the investment for the rolling train 11, measured by the amount produced by the thin-slab casting plant 1, would be relatively high. If a vertical thin-slab casting installation 2 is already present in a plant, it can be expanded by a horizontal thin-slab casting installation in accordance with the invention, so that the economy of the rolling train 11 that is already present is increased, and the production spectrum is expanded.

FIGS. 1 c and 1 d show an embodiment of an installation according to the invention that is similar to the embodiment of FIGS. 1 a and 1 b, but in contrast to the installation shown in FIGS. 1 a and 1 b, the horizontal thin-slab casting installation 1 (shown at the top in FIGS. 1 b and 1 c) is realized with a shorter temperature-adjusting unit 9. Installations of this type can also be operated more efficiently now, although they have only a relatively short temperature-adjusting zone 9 for the temporary storage of the thin or very thin slabs. The rest of the system is equivalent to the system shown in FIGS. 1 a and 1 b.

FIG. 2 a shows a vertical thin-slab casting installation 2 with a downstream rolling train 11 arranged in line with it. Horizontal thin-slab installations 1 of the type already shown in FIGS. 1 b and 1 c are arranged next to this installation. As in the case of the specific embodiments described earlier, slabs can be conveyed or guided by means of conveyors 10 from the two outer thin-slab casting installations 1 or casting lines, preferably from the end of the given temperature-adjusting unit 9, into a section of the temperature-adjusting zone 9 of the middle casting line or thin-slab casting installation 2. As seen in the casting direction, this section is preferably positioned in a middle region of the temperature-adjusting unit 9 of the vertical thin-slab casting installation 2. If slabs arrive in this section from the outer casting lines, they preferably still pass through part of the temperature-adjusting zone 9 and are then fed to the rolling train 11.

FIG. 2 b shows the same system as FIG. 2 a but in a perspective view. The reference numbers refer to the same structures as in FIGS. 1 a to 1 d.

FIGS. 3 a and 3 b show a top view and a perspective view of another embodiment of an installation according to the invention. In this embodiment, three horizontal thin-slab casting installations 1 are arranged side by side, and a downstream rolling train 11 is aligned with or is arranged in line with the thin-slab casting installation 1 that is arranged in the middle of the three installations. As in the previous embodiments, a conveyor system 10 is provided for conveying slabs from the outer installations to the installation or casting line that is arranged in the middle.

FIGS. 4 a and 4 b are analogous to FIGS. 3 a and 3 b, but all of the casting lines are supplied with melt by a common distributing launder 3. In this case, we can also talk of an installation with three or more strands feeding one rolling train 11.

In general, features from all of the figures can be combined with one another, or individual design details can be adapted by the expert to the specific application.

LIST OF REFERENCE NUMBERS

-   1 horizontal thin-slab casting installation -   2 vertical thin-slab casting installation -   3 distributing launder -   4 mold -   5 charging vessel -   6 conveyor belt -   7 bending device/straightening device -   8 cutting device -   9 temperature-adjusting unit -   10 pivoting conveyor -   11 rolling train -   12 roll stand 

1-13. (canceled)
 14. An installation for casting and rolling metal, comprising: at least a first and a second casting line for casting slabs; means for conveying slabs cast in the first casting line into the second casting line; and a rolling train for rolling the cast slabs; wherein the first casting line is a horizontal thin-slab casting installation, which comprises at least one charging vessel for a melt and one horizontally running conveyor belt downstream of the at least one charging vessel in a casting direction; the second casting line is a horizontal thin-slab casting installation or a vertical thin-slab casting installation, which comprises at least one mold for vertical casting of slabs and a bending and straightening device for bending and straightening the vertically cast slab into a horizontal position; and the rolling train for rolling the cast slabs is arranged downstream of one of the two casting lines, and the two or more casting lines and the means of conveying are configured and arranged so that the slabs cast with each one of the casting lines can be fed to the rolling train.
 15. The installation according to claim 14, wherein each of the casting lines is a horizontal thin-slab casting installation, which is followed by the rolling train for rolling the slabs cast in the horizontal thin-slab casting installations.
 16. The installation according to claim 14, wherein the casting lines are designed so that it is possible to cast strips of such small thickness that a roughing stand is not necessary for rolling the cast slabs before the slabs enter the rolling train.
 17. The installation according to claim 14, wherein the vertical thin-slab casting installation is designed for casting slabs with a thickness of 40 mm to 120 mm, and/or the horizontal thin-slab casting installation is designed for casting slabs with a thickness of 5 mm to 35 mm.
 18. The installation according to claim 17, wherein the horizontal thin-slab casting installation is designed for casting slabs with a thickness of 10 mm to 20 mm.
 19. The installation according to claim 14, wherein the horizontal thin-slab casting installations are designed for casting high alloy and super alloy steels.
 20. The installation according to claim 14, further comprising at least one temperature-adjusting device is arranged downstream of the conveyor belt of the thin-slab casting installations in the direction of casting, and/or at least one temperature-adjusting device is arranged downstream of the bending and straightening device of the vertical thin-slab casting installation in the direction of casting.
 21. The installation according to claim 20, wherein the at least one temperature-adjusting device is a furnace.
 22. The installation according to claim 20, wherein the means for conveying slabs includes conveyors.
 23. The installation according to claim 22 wherein the conveyors are designed so that the slabs are conveyed into a section of the temperature-adjusting device of another of the casting lines.
 24. The installation according to claim 20, wherein the conveyors are pivoting conveyors.
 25. The installation according to claim 14, wherein the casting lines are arranged parallel to each other and/or side by side.
 26. The installation according to claim 14, including a total of three casting lines arranged parallel side by side, and the rolling train for rolling the slabs cast in the casting lines is arranged downstream of and/or in line with a middle of the three casting lines in the direction of casting.
 27. A method for casting and rolling metal with at least two casting lines for casting slabs, comprising the steps of: casting thin slabs horizontally in at least one casting line; and casting thin slabs horizontally in at least one other casting line; and/or vertically casting slabs and bending the slabs into a horizontal direction, and subsequently feeding the cast slabs to exactly one rolling train.
 28. The method according to claim 27, wherein the horizontally cast thin slabs consist of steels with an aluminum content of up to 10%.
 29. The method according to claim 28, wherein the horizontally cast thin slabs consist of steels with an aluminum content of 1-3%.
 30. The method according to claim 27, wherein the horizontally cast thin slabs consist of carbon steels, low alloy steels, high alloy steels, or peritectic steels. 